October 30, 2012
Earliest Star Formation Stage Observed By Astronomers
Lee Rannals for redOrbit.com - Your Universe Online
They managed to also identify a previously unobserved class of object that could be the earliest known precursor of the birth of massive stars.
By combining the Herschel Space Telescope's sharpness and sensitivity in the far-infrared range with a method encountered in visual effects companies, they were able to construct the most realistic 3D model of the cloud to date.
The method uses raytracing, which involves tracing the line of sight back into the object being observed. Raytracing is commonly used to provide realistic-looking computer-generated creatures, objects or whole scenes.
The method helped to match up light emitted within Barnard 68 at different wavelengths with simplified models of the cloud's three-dimensional shape, density and temperature distribution.
"The results have shaken up some of what astronomers thought they knew about this cloud," MPIA wrote in a recent prepared statement. "The emerging picture is one of Barnard 68 condensing from a drawn-out filament, heated by unevenly distributed external radiation from the direction of the central plane of our home galaxy."
The team also found some signs pointing a cloud fragment in collision with Barnard 68, which could lead to the cloud's collapse and the formation of one or more low-mass stars.
Barnard 68 is considered to be relatively small, and clouds of its stature will give birth to a few low-mass stars at most. In order to have another perspective, MPIA's Sarah Ragan used Herschel to find out how massive stars are born in significantly more massive dark clouds.
Stars that are about to be born are called "protostars" and Herschel enables astronomers to find some of the youngest and most primitive protostars known.
The new observations swelled the ranks of known protostars from 330 to nearly 500, leading to the discovery of a new type of not-quite-a-star, which consists of a region sitting at 15 degrees above absolute zero with no sign of a protostar.
This region is likely an early precursor stage of star formation, and is a phase that could last less than 1,000 years.
"Studying these elusive, pristine objects lays a necessary foundation for all subsequent studies of star formation," the MPIA researcher said.
The team published their findings in the Astronomy & Astrophysics journal.